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Impact Of Virtual Building Model And Thermostat Installation On Performance And Dynamics Of Variable-Speed Equipment During Load-Based Tests, Li Cheng, Akash Patil, Parveen Dhillon, James E. Braun, W. Travis Horton Jan 2018

Impact Of Virtual Building Model And Thermostat Installation On Performance And Dynamics Of Variable-Speed Equipment During Load-Based Tests, Li Cheng, Akash Patil, Parveen Dhillon, James E. Braun, W. Travis Horton

International Refrigeration and Air Conditioning Conference

To better characterize the performance of variable-speed DX (Direct Expansion) equipment in a laboratory environment, a load-based psychrometric chamber testing methodology has been developed as an alternative to existing steady-state testing approaches. The methodology allows equipment to respond dynamically to a virtual building model using its integrated controls. To mimic an actual building, a virtual building model incorporates sensible and latent loads along with simple lumped capacitance building dynamics that interact with the variable-speed equipment. The rated capacity of the test equipment is used along with a specified sizing factor and target sensible heat ratio (SHR) to specify the building …

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Experimental Study Of Frost Accretion On Hydrophilic And Hydrophobic Substrates Under Forced Convection Conditions, Valter Nascimento, Felipe Loyola, Christian Hermes, Rodrigo P. Cardoso, Andrew Sommers Jan 2018

Experimental Study Of Frost Accretion On Hydrophilic And Hydrophobic Substrates Under Forced Convection Conditions, Valter Nascimento, Felipe Loyola, Christian Hermes, Rodrigo P. Cardoso, Andrew Sommers

International Refrigeration and Air Conditioning Conference

The present study is aimed at investigating, by means of an experimental approach, the effect of surface wettability on the frost accretion over horizontal flat surfaces under forced convection conditions. A purpose-built closed-loop wind-tunnel facility was especially designed and constructed to provide a strict control of the psychrometric conditions at the entrance of the test section, and also of the plate surface temperature. An image acquisition system was used to measure the thickness of the frost layer over time. A dataset comprised of more than 800 experimental data points spanning different surface temperatures (from -20 to -10°C) and air temperatures …

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Thermodynamic Design Of A Mesoscale Vapor Compression Cooling Device, Ricardo Yee, Christian Hermes Jan 2018

Thermodynamic Design Of A Mesoscale Vapor Compression Cooling Device, Ricardo Yee, Christian Hermes

International Refrigeration and Air Conditioning Conference

This paper presents a thermodynamic methodology for designing a vapor compression refrigeration system aiming at electronics cooling. A cycle simulation model was developed firstly assuming isentropic compression and isenthalpic expansion, whereas the heat exchangers (condenser and evaporator) were modelled following a distributed approach. Whilst a 3-D heat conduction model calculates the heat leakage from the condenser to the evaporator, 2-D heat conduction models provide the temperature distribution (and the heat transfer rates) at the cold and hot ends. The fluid flow was modelled as 1-D considering both the momentum and the energy conservation equations to design the heat exchangers geometry …

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A Design Approach For Liquid Separators Applied To Household Refrigerators, Isabel Janke, Alexsandro Dos Santos Silveira, Joel Boeng Jan 2018

A Design Approach For Liquid Separators Applied To Household Refrigerators, Isabel Janke, Alexsandro Dos Santos Silveira, Joel Boeng

International Refrigeration and Air Conditioning Conference

The objective of this study was to develop a methodology for designing a T-junction liquid-vapor separator for household refrigerators. The influence of the following independent parameters on the separator performance was studied: i) refrigerant mass flow rate, ii) inlet vapor quality, iii) evaporation temperature, iv) critical droplet diameter, v) critical bubble diameter and vi) suction ratio. For modeling purposes, the T-junction was divided into three sub-models: inlet, vapor and liquid branches. The inlet branch sub-model revealed that a proper phase separation occurs with larger diameters as the refrigerant mass flow rate and vapor quality increase. The dimensions of the vapor …

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Cfd Simulation Of Vortex Flashing Flows In Convergent-Divergent Nozzles, Jingwei Zhu, Stefan Elbel Jan 2018

Cfd Simulation Of Vortex Flashing Flows In Convergent-Divergent Nozzles, Jingwei Zhu, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Vortex control is a novel two-phase convergent-divergent nozzle restrictiveness control mechanism by adjustable nozzle inlet vortex. It requires no change to the physical dimensions of the nozzle geometry. A nozzle with inlet vortex was called vortex nozzle (or swirl nozzle). Previous experiments on vortex nozzle with initially subcooled R134a showed that the nozzle becomes more restrictive as the strength of the inlet vortex increases. The maximum vortex control range has been observed to be 42% of maximum choked total mass flow rate through the nozzle. The control range of inlet pressures and mass flow rates that can be achieved by …

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Theoretical And Experimental Evaluation Of Microchannel Condensers Applied To Household Refrigerators, Renata Soares Rametta, Joel Boeng, Joel Boeng Jan 2018

Theoretical And Experimental Evaluation Of Microchannel Condensers Applied To Household Refrigerators, Renata Soares Rametta, Joel Boeng, Joel Boeng

International Refrigeration and Air Conditioning Conference

The aim of this work is to study, theoretically and experimentally, the impact of using forced-draft microchannel condensers in a specific model of household refrigerator. To this end, a mathematical model was developed to predict the condenser heat released rate and the air-side pressure drop as a function of geometry and operating conditions. This model was then added to an existing simulation platform of household refrigerators, in an attempt to study the effect of the heat exchanger on the appliance performance. Experiments were carried out in an open-type wind tunnel and in a climate-controlled test chamber, to validate both the …

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Performance Analysis Of Active Magnetic Regenerative Refrigeration Cycle Using Transient Modeling, Minwoong Kang, Stefan Elbel Jan 2018

Performance Analysis Of Active Magnetic Regenerative Refrigeration Cycle Using Transient Modeling, Minwoong Kang, Stefan Elbel

International Refrigeration and Air Conditioning Conference

This paper evaluates the performance of an active magnetic regenerative refrigeration cycle (AMRRC) by using a transient modeling tools. While theoretical COPs of magnetic refrigeration systems are quite promising, parasitic losses inherent to the cycle can substantially reduce the energy efficiency that can be achieved in reality. For solid state refrigeration systems, such as the AMRR cycle, the regenerator undergoes cyclic heating and cooling, making the thermal capacitance of the component a critical parameter during no flow periods. Additional performance reductions are experienced due to additional temperature differences required to convect heat into and out of the magnetic regenerator through …

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Application Of Vortex And Pulsation Coolers In Technologies Of Rare Gases Extraction, Vitaly Bondarenko, Iurii Symonenko, Dmytro Tyshko Jan 2018

Application Of Vortex And Pulsation Coolers In Technologies Of Rare Gases Extraction, Vitaly Bondarenko, Iurii Symonenko, Dmytro Tyshko

International Refrigeration and Air Conditioning Conference

Two types of gas-dynamic coolers were considered: Rank-Hilsh vortex tubes and resonance tubes, known as devices of Hartmann-Sprenger. These devices have a number of similar physical and structural features: no moving parts, low inertia, environment safety, they can be sources of cold and heat simultaneously, generate pressure pulse, and separate gas mixtures. Gas-dynamic devices can be used in the technologies of rare gases obtaining as coolers of reflux condensers. They use pressure drop and don’t need in additional energy consumption. The temperature drop of mixtures phase equilibrium allows to reduce the concentration of by-products. Due to this, costs of gas …

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Viability Of Various Ignition Sources To Ignite A2l Refrigerant Leaks, Dennis K. Kim, Peter B. Sunderland Jan 2018

Viability Of Various Ignition Sources To Ignite A2l Refrigerant Leaks, Dennis K. Kim, Peter B. Sunderland

International Refrigeration and Air Conditioning Conference

An international drive toward sustainability of refrigeration systems will require the adoption of low global warming potential (GWP) refrigerants. Most of these are mildly flammable. Low-GWP refrigerants are generally well characterized in terms of their lower flammability limits, heats of combustion, and flame speeds. However, they are poorly understood in terms of their susceptibility to ignition from sources commonly encountered in residential and industrial settings, including motors, electric arcs, hot surfaces, and open flames. This important gap in understanding is the focus of this project. The primary objective of this project was to perform tests to determine the viability of …

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Impact Of Liquid/Vapor Maldistribution On The Performance Of A Plate Heat Exchanger Evaporator For Pure And Mixed Refrigerants, Roberta Mancini, Vikrant Chandramohan Aute, Wiebke Brix Markussen, Brian Elmegaard Jan 2018

Impact Of Liquid/Vapor Maldistribution On The Performance Of A Plate Heat Exchanger Evaporator For Pure And Mixed Refrigerants, Roberta Mancini, Vikrant Chandramohan Aute, Wiebke Brix Markussen, Brian Elmegaard

International Refrigeration and Air Conditioning Conference

This paper presents an estimation of the degradation in heat transfer performance in plate heat exchanger (PHE) evaporators due to flow maldistribution. A booster heat pump system integrated in a district heating network is used as a case study. Butane and two zeotropic mixtures, namely Propylene/Butane (0.5/0.5) and R1234yf/R1233zdE (0.5/0.5) were evaluated as working fluids. The PHE was preliminarily sized for all the refrigerants by considering a fixed plate geometry from a commercial manufacturer. A two-dimensional (2D) numerical model was developed for the evaluation of the total heat flow rate degradation due to the imposed uneven liquid/vapor distribution at the …

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Modeling And Experimental Study On A Direct Expansion Based Enhanced Dehumidification Air Conditioning System, Wenjing Chen, Ming-Yin Chan, Wen Bing Weng, Shi Ming Deng Jan 2018

Modeling And Experimental Study On A Direct Expansion Based Enhanced Dehumidification Air Conditioning System, Wenjing Chen, Ming-Yin Chan, Wen Bing Weng, Shi Ming Deng

International Refrigeration and Air Conditioning Conference

Direct expansion (DX) air conditioning (A/C) systems are widely used for controlling indoor air temperature and humidity in various buildings in hot and humid climates since they are simpler and more energy efficient, and generally cost less to own and maintain. However, it is often problematic for a DX A/C system to provide desired humidity control due to the current system design trends, variable weather conditions and the commonly used control strategies for DX A/C systems. Therefore, a standalone DX based enhanced dehumidification air conditioning (EDAC) system is proposed to provide suitable indoor humidity control at different seasons. There are …

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Experimental Study Of A R407c Liquid-To-Water Heat Pump With Domestic Hot Water Production, Ignacio Ortega, Jaime Sieres Atienza, Fernando Cerdeira, Estrella Alvarez Jan 2018

Experimental Study Of A R407c Liquid-To-Water Heat Pump With Domestic Hot Water Production, Ignacio Ortega, Jaime Sieres Atienza, Fernando Cerdeira, Estrella Alvarez

International Refrigeration and Air Conditioning Conference

Currently, a number of companies manufacture liquid-to-water heat pumps for geothermal applications, based on the scroll compressor technology and using refrigerant R407C. The performance of this kind of machines depends greatly on the operating conditions, basically on the temperature levels of the liquid and water fluids. This paper presents an experimental study of a liquid-to-water heat pump with the possibility of domestic hot water production. The refrigerant used is R407C. The main components of the heat pump are a scroll type compressor, a desuperheater for hot water production, two brazed plate heat exchangers (condenser and evaporator) and a thermostatic expansion …

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Alternative Refrigerants For Household Refrigerators, Mario Straub Jan 2018

Alternative Refrigerants For Household Refrigerators, Mario Straub

International Refrigeration and Air Conditioning Conference

During the last decades, the energy consumption of household appliances was reduced continuously. The reason for this developments is caused by higher power costs and stricter statutory rules. To achieve these goals, it was necessary to improve and evolve each component of the cooling circuit as well as the insulation. For instance: On the compressors side: Introduction of variable speed compressors In the heat exchangers: Improvement of heat transfer (e.g. using fans, new geometry etc.) Expansion device: Further development of the inner heat exchanger between capillary tube and suction line Insulation of the cabinet: Improvement of the gaskets and introduction …

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Evaluation The Effect Of Washing On The Heat Transfer Capacity And Air-Side Flow Resistance Of Air Cooled Condensers, Mehdi Mehrabi, David P. Yuill Jan 2018

Evaluation The Effect Of Washing On The Heat Transfer Capacity And Air-Side Flow Resistance Of Air Cooled Condensers, Mehdi Mehrabi, David P. Yuill

International Refrigeration and Air Conditioning Conference

Air cooled condensers are commonly used in rooftop units and residential air-conditioners to reject heat outdoors. Airborne particles in the environment, such as dust, grass, leaves, seeds, and anthropogenic agents, can foul the air side of the condensers. Therefore, it is common practice to regularly clean the air side of condensers. Seven fouled wavy fin, and two fouled spiny fin condensers from residential condensing units were collected at the end of their service lives, and examined in the laboratory to study the effect of the fouling on heat transfer capacity and air-side flow resistance. A test apparatus was designed and …

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Pros & Cons Of Using Hot-Wall Condensers In Household Refrigerators, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Claudio Melo Jan 2018

Pros & Cons Of Using Hot-Wall Condensers In Household Refrigerators, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Claudio Melo

International Refrigeration and Air Conditioning Conference

This work focuses on the pros and cons of using hot-wall condensers in household refrigerators, based both in numerical and experimental approaches. To this end, eight different refrigerator samples of the same model were manufactured with distinct designs of hot-wall condensers. The design parameters were the following: (i) adhesive tape (aluminum or polyethylene), (ii) tube outer diameter (4 or 4.76 m), (iii) total length (10 or 11.5 m) and (iv) lay-out. An in-house mathematical model for hot-wall condensers was added to an in-house system simulation tool to predict the samples performance. Experiments were also conducted in a climate-controlled test chamber …

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Energy Saving Potential Of A Temperature Test Chamber By Implementing A Heat-Pump, Andreas Wagner, Thomas Tannert, Ullrich Hesse Jan 2018

Energy Saving Potential Of A Temperature Test Chamber By Implementing A Heat-Pump, Andreas Wagner, Thomas Tannert, Ullrich Hesse

International Refrigeration and Air Conditioning Conference

Energy savings become more and more important – also for the rather small industry sector of environmental simulation. So far the technical focus was mainly to realize challenging test cycles which are often gives as temperature profiles. The energy efficiency of the test devices are not specified by any standard. Nevertheless, especially test cycles with intermittent cooling and heating over a wide temperature range need a substantial electrical energy input. As state-of-the-art technology for cooling a vapor compression cycle and for heating an electrical heater is used. In this work a standard temperature test chamber with a specified temperature range …

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A2l Refrigerants Leaks And Ignitions Testing Under Whole Room Scale, Xudong Wang, Pravin Gandhi Jan 2018

A2l Refrigerants Leaks And Ignitions Testing Under Whole Room Scale, Xudong Wang, Pravin Gandhi

International Refrigeration and Air Conditioning Conference

Environmental concerns raised by high global warming potential (GWP) refrigerants have triggered a series of activities around the world to curtail the use of hydrofluorocarbons (HFCs). Many of the promising alternative refrigerants being investigated are mildly flammable and fall under the A2L safety classification of ASHRAE 34. In an effort to properly address A2L refrigerants in safety standards, the Air-Conditioning, Heating, and Refrigeration Technology Institute (AHRTI) undertook a research project to investigate refrigerant leaks and ignition testing under whole scale room conditions. This paper summarizes refrigerant leak and ignition tests for A2L refrigerants R-32, R-452B, R-455A and R-457A. The work …

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Dynamic Optimal Control Of A Co2 Heat Pump Coupled With Hot And Cold Thermal Storages, Fang Liu, Jiaxin Deng, Eckhard A. Groll Jan 2018

Dynamic Optimal Control Of A Co2 Heat Pump Coupled With Hot And Cold Thermal Storages, Fang Liu, Jiaxin Deng, Eckhard A. Groll

International Refrigeration and Air Conditioning Conference

This study presents a model-based dynamic optimization strategy for a dual-mode CO2 heat pump coupled with hot and cold thermal storages, which was proposed as a high-efficiency smart grid enabling option in heating and cooling services for buildings or industry. Dynamic optimal control for simultaneously charging of hot and cold thermal storages is very delicate. The optimal control of compressor discharge pressure were commonly used for optimal control of heat pump systems. In this study, the outlet water temperatures of hot and cold tanks are used as indicators in the dynamic optimal strategy for charging of hot and cold storages …

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Improving Performance Of An Existing Heat Pump: A Case Study, Vijay Bahel, Scott Lanzer, Suresh Shivashankar, Cory Ostendorf Jan 2018

Improving Performance Of An Existing Heat Pump: A Case Study, Vijay Bahel, Scott Lanzer, Suresh Shivashankar, Cory Ostendorf

International Refrigeration and Air Conditioning Conference

Improving Performance of an Existing Heat Pump: A Case Study Vijay Bahel, Scott Lanzer and Suresh Shivashankar Emerson Climate Technologies Sidney, Ohio 45365, USA Phone: 937-498-3643, Fax: 937-498-3203 Email: [email protected] Abstract This paper presents the findings of a case study used to identify the design options for upgrading the performance of an Air Source Heat Pump with minimum design changes to the system chassis. We used Emerson’s Steady-State System Model to identify opportunities for improving the baseline SEER. Our starting point was a nominal Fixed Capacity 5 ton, 14 SEER Heat Pump using Refrigerant R-410a. In this exercise we identified …

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Condensation Heat Transfer Of R22, R410a And R32 Inside A Multiport Mini-Channel Tube, Pham-Quang Vu, Kwang-Il Choi, Jong-Taek Oh, Honggi Cho Jan 2018

Condensation Heat Transfer Of R22, R410a And R32 Inside A Multiport Mini-Channel Tube, Pham-Quang Vu, Kwang-Il Choi, Jong-Taek Oh, Honggi Cho

International Refrigeration and Air Conditioning Conference

In the present study, the heat transfer coefficients are investigated experimentally for condensation of R22, R410A, and R32 inside a horizontal multiport rectangular mini-channel tube. The multiport tube having nine channels in 0.969mm of hydraulic diameter, the experimental measurements were carried out at the fixed saturation temperature of 48oC, by the varying refrigerant mass flux from 50 to 500kg/m2s, and the heat flux range from 3 to 15kW/m2. The test section was a double tube of counter-flow type; the refrigerant was flowed condensation inside the test tube by heat exchange with cooling water flowing in the annular side. The temperature …

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R134a And Its Low Gwp Substitutes R1234yf And R1234ze(E) Condensation Inside A 4mm Horizontal Smooth Tube, Giovanni A. Longo, Andrea Diani, Giulia Righetti, Claudio Zilio Jan 2018

R134a And Its Low Gwp Substitutes R1234yf And R1234ze(E) Condensation Inside A 4mm Horizontal Smooth Tube, Giovanni A. Longo, Andrea Diani, Giulia Righetti, Claudio Zilio

International Refrigeration and Air Conditioning Conference

The substitution of HFC134a with low GWP refrigerants is one of the most important challenge for refrigeration and air conditioning. The possible substitutes include natural refrigerants, such as HC600 (Butane) and HC600a (Isobutane), and also synthetic refrigerants, such as HFO1234yf and HFO1234ze(E). The HC refrigerants exhibit very low GWP, 3 and 4 HC600a and HC600 respectively, good thermodynamic and transport properties, and pressure and volumetric performance very similar to HFC134a. The major drawback of HC refrigerants is their high flammability, being classified in class A3 according to ASHRAE classification. Also the HFO refrigerants present a mild flammability, being classified in …

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Additive Manufacturing Of Heat Exchangers, Jake Boxleitner, Gregory F. Nellis Jan 2018

Additive Manufacturing Of Heat Exchangers, Jake Boxleitner, Gregory F. Nellis

International Refrigeration and Air Conditioning Conference

The Advanced Research Project Agency (ARPA) includes the Advanced Research In Dry cooling (ARID) program. The objective of the ARID program is to develop technologies that allow power plants to achieve high thermal-to-electric energy conversion efficiency with zero net water consumption. The most direct method of achieving this goal is to improve the thermal efficiency of dry-cooled condensers by reducing the air-side thermal resistance without significantly increasing either the capital cost or the fan power required to operate these devices. One approach to this is the application of additive manufacturing to dry cooled condensers in order to obtain a low …

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Cooling Systems At Temperature Level T=28…30 K, Vitaly Bondarenko, Iurii Symonenko, Artem Chyhrin Jan 2018

Cooling Systems At Temperature Level T=28…30 K, Vitaly Bondarenko, Iurii Symonenko, Artem Chyhrin

International Refrigeration and Air Conditioning Conference

Rectification is an effective method for the Ne-He mixture separating. This method is also used at separation of neon into isotopic components (isotopes 20Ne, 21Ne and 22Ne). It is required to maintain temperatures around 28 K at the pressure of rectification column close to atmospheric pressure. This task has several solutions. Diverse cryogenic cycles, a lot of methods for removing heat and various refrigerants can be used. The simplest method of cooling the column, which is practiced in the Ne-He separation, involves the supplying the refrigerant (98 % Ne) in the top of the rectification unit. For obtaining of stable …

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Numerical Simulation Of Fault Impacts For Commercial Walk-In Freezers, Alireza Behfar, David P. Yuill Jan 2018

Numerical Simulation Of Fault Impacts For Commercial Walk-In Freezers, Alireza Behfar, David P. Yuill

International Refrigeration and Air Conditioning Conference

Refrigeration systems can undergo many faults that could negatively affect their operation and performance. This paper describes a modeling process to simulate the fault impacts on the operation of a commercial walk-in freezer using semi-empirical models. These models often require less modeling effort than full forward models and could be used in scenarios where detailed information is missing, such as in field-measured systems. An important characteristic of a typical walk-in refrigeration system is the existence of a liquid-line receiver after the condenser, which significantly changes the behavior of the cycle, in comparison to a receiver-less system. Component models described in …

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Assessing The Impact Of Using Very Low Gwp Alternatives To R-404a, Stephen Spletzer, Jethro Medina, Joshua Hughes Jan 2018

Assessing The Impact Of Using Very Low Gwp Alternatives To R-404a, Stephen Spletzer, Jethro Medina, Joshua Hughes

International Refrigeration and Air Conditioning Conference

Global pressures on hydrofluorocarbon (HFC) refrigerants have reached new levels. With ongoing country ratifications of the Kigali Amendment to the Montreal Protocol and refrigerant shortages across Europe driven by the F-Gas regulations, equipment manufacturers are working hard to implement lower global warming potential (GWP) solutions. R-404A is one of the higher GWP refrigerants (GWP100 Year = 3,922, per AR4) used widely in commercial refrigeration. Several very low GWP (LGWP) candidates have emerged as potential replacements. For many hermetic and split system applications, hydrofluoroolefin-based (HFO) blends represent lower flammability alternatives to hydrocarbon (HC) refrigerants, that also allow for significantly larger charge …

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Design Of A Cascade Refrigeration System For Applications Below -50°C Using Co2-Sublimation, Yixia Xu, Robin Langebach, Ullrich Hesse Jan 2018

Design Of A Cascade Refrigeration System For Applications Below -50°C Using Co2-Sublimation, Yixia Xu, Robin Langebach, Ullrich Hesse

International Refrigeration and Air Conditioning Conference

Trifluoromethane (R-23) is currently the most widely used non-flammable refrigerant for applications down to about -80°C (193K). However, R-23 has an enormous global warming potential (GWP100=14800) and recent price increases lead to a loss of attractiveness in industry. As an alternative, some studies in recent years indicated the possibility of extending the application temperature of the natural refrigerant carbon dioxide (CO2) beneath its triple conditions in a refrigeration cycle. Thus there would be a great potential for CO2 to replace R-23. In present paper, the design of a cascade refrigeration machine using CO2-sublimation is introduced. R-452A is used as refrigerant …

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Numerical And Experimental Random Spectral Analysis Of A Condensing Unit Discharge Tube, Guilherme Espindola, Emilio Rodrigues Hulse, Diego Beppler Jan 2018

Numerical And Experimental Random Spectral Analysis Of A Condensing Unit Discharge Tube, Guilherme Espindola, Emilio Rodrigues Hulse, Diego Beppler

International Refrigeration and Air Conditioning Conference

Transportation is a factor of paramount importance on the life cycle of manufactured goods. Components are in constant movement in the production line, the product is transported to one or more distributors and then to the final costumer. During the transport, all components are subjected to vibration. Such vibrations depend on several factors, like transportation method (Truck, Train, Air, …), vehicle suspension type (Spring, Air, ...), road and rails quality, etc. Due to the unknown nature of all components involved, these vibrations are usually assumed to depict random characteristics, resulting in a somewhat random stress in the components. Most of …

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The Influence Of Lubricant In Hfc & Hfo Blend Refrigeration System, Yu-Kai Chen, Jung-Tsung Hung, Hsu-Hua Tang, Jeng-Shiang Tsaih Jan 2018

The Influence Of Lubricant In Hfc & Hfo Blend Refrigeration System, Yu-Kai Chen, Jung-Tsung Hung, Hsu-Hua Tang, Jeng-Shiang Tsaih

International Refrigeration and Air Conditioning Conference

Although HFO refrigerants are considered the low GWP solutions to the global warming problem, some properties of HFO refrigerants prohibited the direct drop in replacement application in the refrigeration system. As a result, to replace the high GWP HFC refrigerants, HFC & HFO refrigerants are blended to combine their properties to become a workable solution. Both HFC and HFO refrigerants have similar basic properties; however, one of the HFO refrigerants properties is good miscibility to incumbent refrigeration lubricants, especially HFO-1234ze. Generally speaking, refrigerant-oil mixture with highly miscible property in low temperature evaporator will lead to more soluble phenomenon in high …

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Performance Evaluation Of Heat Pump Cycle Using Low Gwp Refrigerant Mixtures Of Hfc-32 And Hfo-1123, Shigeru Koyama, Takahiko Miyazaki, Junki Hirayama, Nobuo Takata, Yukihiro Higashi Jan 2018

Performance Evaluation Of Heat Pump Cycle Using Low Gwp Refrigerant Mixtures Of Hfc-32 And Hfo-1123, Shigeru Koyama, Takahiko Miyazaki, Junki Hirayama, Nobuo Takata, Yukihiro Higashi

International Refrigeration and Air Conditioning Conference

Hydro-fluorocarbons (HFCs) have been widely used as working fluids (refrigerants) in air-conditioning and refrigeration systems. At the 1997 Kyoto Conference (COP3), a worldwide agreement was obtained to regulate the production and use of HFCs exhibit high global warming potential (GWP). In the above situation, Hydro-fluoro Olefins (HFOs) having extremely low GWP values such as HFO-1234yf, HFO-1234ze(E), HFO-1123, has attracted attentions. In this study, the performance of heat pump cycle using low GWP refrigerant mixtures of HFC-32 and HFO-1123 is evaluated experimentally. The experimental system is a water heat source vapor compression cycle, mainly composed of an inverter-controlled & hermetic-type scroll …

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Novel Visualization Method To Quantify Local Air-Side Heat Transfer Coefficient, Min Che, Stefan Elbel Jan 2018

Novel Visualization Method To Quantify Local Air-Side Heat Transfer Coefficient, Min Che, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Low air-side heat transfer coefficients (HTC) are often the bottleneck of heat exchanger performance. However, the measurement of local air-side heat transfer coefficients for the entire heat transfer surface is not a trivial task. Current experimental methods often only work on scaled-up samples which typically cannot deliver continuous HTC distributions across the surface of interest. Moreover, some methods require very precise and costly equipment such as lasers. Therefore, a novel visualization method is designed to obtain local air-side HTC distributions of an entire heat exchanger with a relatively simple experimental facility. The method relies on measuring mass transfer and applying …

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